KR100993980B1 - Method for Manufacturing Molten Pig Iron in Blast Furnace - Google Patents

Abstract

The present invention relates to a blast furnace operation method for manufacturing molten iron by charging iron ore and coke into the blast furnace adopting a stave cooling system as a blast furnace furnace cooling system, and controls the charging pattern of the charges based on the furnace heat load to control the overall breathability. It is to provide a blast furnace operation method that can secure the stability and high productivity of the operation by securing a balanced gas flow in each circumferential direction by appropriately secured.

In the blast furnace operation method, the furnace heat load measured by measuring the heat load of the furnace using the calorie loss of the cooling water supplied to the stave is 22-25 of the total coke charging amount when the furnace heat load is 17,000 to 30,000 Mcal / hr. When% coke is charged in areas 1 and 2, and the measured furnace heat load is 17,000 Mcal / hr or less, 10 to 18% of coke is charged in area 2, and 10 to 10 of the total coke content is charged. 13% of the central coke is charged in area 11, and if the measured furnace heat load is 30,000 Mcal / hr or more, 15-20% of the coke is charged in areas 1 and 2, and the total coke is charged. The main point of the blast furnace operation method is characterized in that 20 to 35% of the coke is charged in the 11th area.

Blast furnace, stave, furnace heat load, coke, center coke, coolant temperature

Description

Method for Manufacturing Molten Pig Iron in Blast Furnace}

1 is a schematic view showing a conventional blast furnace operation

Figure 2 is a schematic diagram showing the distribution of the contents of the furnace at the time of charging the charge according to the conventional method, (a) shows that during normal operation, (b) shows that under the furnace body inert.

3 is a schematic diagram showing the area ratio by area in the blast furnace radial direction;

4 is a furnace temperature distribution diagram in a blast furnace operation according to the prior art

Figure 5 is a schematic diagram showing the distribution of the furnace in the furnace when charging the charge according to the present invention

Explanation of symbols on the main parts of the drawings

One . . . Old body 2. . . Scapfold 3. . . Scap 4. . . Core

5. . . Softening Fusion Table

The present invention relates to a blast furnace operation method for manufacturing molten iron by charging iron ore and coke into the blast furnace adopting a stave cooling system as a blast furnace furnace cooling system, and more specifically, to control the charging pattern of the charge based on the furnace heat load. The present invention relates to a blast furnace operation method that can ensure the stability of the operation.

In general, when the stave cooling system is used as a blast furnace furnace cooling system, the cooling efficiency is superior to that when the cooling panel is used as the blast furnace furnace cooling system.

However, as shown in FIG. 1, when the stave cooling system is used as a blast furnace furnace cooling system, a scaffold 2 is provided at the upper part of the furnace body 1, and a scab 3 at the lower part thereof. ) Is easily formed or dropped.

That is, as the age of operation progresses, the wear amount of the rear surface of the cast iron stave is increased (for example, the thickness of the stave: 300 mm from the first 440 mm → 2 years), and this wear causes uneven internal surface of the furnace body. The formation of scaffolds and scabs in the furnace is promoted, and the generated scaffolds form a mixed layer of coke and ore that lowers the wall, resulting in gaseous imbalance of the cylinder.

In addition, when the cap 3 falls off and falls to the bottom of the furnace, the molten metal temperature of the bottom is drastically lowered, which makes it difficult to discharge the melt and provides a cause of variation in the molten iron temperature in the circumferential direction.

In addition, as the O (iron ore) / C (coke) ratio of the blast furnace operation increases, the amount of charged coke in the blast furnace decreases, and the amount of ore increases, making it difficult to secure air permeability in the blast furnace. As a result, the cause of reaching the inertness of the blast furnace core 4 has been provided.

In order to solve the above problems in the blast furnace operation using the stave cooling system as the blast furnace furnace cooling system, there is a method of activating the furnace wall periphery.

However, in the conventional method, the furnace heat load is increased due to excessive ambient flow (Heat Load:> 25000 Mcal / hr), and the gas flow imbalance in the circumferential direction is accelerated to secure the gas flow to the center. Inadequately, there is a problem of lowering productivity by causing the formation of a typical W-type soft fusion zone 5, which impedes operation.

The present invention is to provide a blast furnace operation method that can achieve the stability and high productivity of the operation by securing a balanced gas flow in the circumferential direction by controlling the charging pattern of the charge based on the heat load of the furnace to ensure the overall air permeability appropriately , Its purpose is.

In addition, the present invention can improve productivity by maintaining a stable operation even under high O / C ratio by appropriately controlling the charging pattern of the charge and the temperature of the cooling water supplied to the stave based on the furnace heat load amount to ensure the overall air permeability It is to provide a blast furnace operation method, which has a purpose.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention mixes coke, central coke, and lumped coke by a turning chute installed therein using a stave blast furnace that supplies cooling water to a stave provided in the main body to cool the main body. In the blast furnace operation method of charging molten iron ore in order to produce a molten iron,

Dividing the interior of the blast furnace into eleven regions (notches) in the radial direction from its inner wall towards the center, and numbering the areas from one to eleven in order from the inner wall to the center;

The amount of mixed coke mixed with the iron ore is 10 to 15% of the total amount of coke charged;

When the furnace heat load measured by measuring the heat load of the furnace using the heat loss of the cooling water supplied to the stave is 17,000 to 30,000 Mcal / hr, the coke of 22-25% of the total coke charge is 1 and 2 areas. Charged in the main coke, 10-13% of the total coke content is charged in area 11, the remaining coke is loaded in areas 3-9, and the intermediate coke mixed iron ore is charged in areas 3-9. ;

When the measured heat load of the furnace body is 17,000 Mcal / hr or less, 10 to 18% of the coke content of coke is charged in area 2, and 10 to 13% of the coke content of the coke is charged to area 11, The remaining coke is charged in zones 3-9, and the lumped coke mixed iron ore is charged in zones 5-9; And

If the measured furnace heat load is 30,000 Mcal / hr or more, 15 to 20% of the coke content of coke is charged in areas 1 and 2, and 20 to 35% of the total coke content of coke is in area 11 Charging, the remaining coke is charged in the 3 to 9 area, and the crushed coke mixed iron ore is charged to the 2 to 7 area blast furnace operation method characterized in that.                     

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention mixes coke, central coke, and lumped coke by a turning chute installed therein using a stave blast furnace that supplies cooling water to a stave provided in the main body to cool the main body. It is preferably applied to the blast furnace operation method of charging molten iron ore in order to produce molten iron.

The interior of the blast furnace is divided into eleven regions (notches) in the radial direction from the inner wall toward the center, and the regions are numbered in sequence from 1 to 11 as they go from the inner wall to the center.

Supply of the charges to the respective areas is made by controlling the angle of the turning chute as shown in Table 1 below.

Notch Number (Area Number) One 2 3 4 5 6 7 8 9 10 11 Chute angle (°) 46.5 44.5 42.5 40.5 38 35.5 32.5 29.5 26 22 3

The iron ore is mixed with lumped coke and charged into the blast furnace, and the mixing amount is preferably set to 10 to 15% of the total coke loading.

The lumped coke is mixed with iron ore in order to prevent the deterioration of breathability resulting from the particle size difference between iron ore and coke. If the mixing amount is too small, the mixing effect is insufficient and the breathability is deteriorated. Since the amount is small, there is a risk of non-uniform gas generation in the furnace. Therefore, the mixing amount is preferably set to 10 to 15% of the total amount of coke charged.

In the present invention, when the heat load of the furnace body measured by measuring the heat load of the furnace using the heat loss of the cooling water supplied to the stave is 17,000 to 30,000 Mcal / hr, coke of 22-25% of the total coke charge is 1 And charging into zone 2, charging 10 to 13% of the central coke in the total coke loading into zone 11, charging the remaining coke into zones 3 to 9, and loading the intermediate coke mixed iron ore 3 to 9 times. Charge into the area.

If the amount of coke charged in the area 1 and 2 is too small, there is a high possibility of inert phenomenon at the lower part due to the small amount of gas in the periphery, and too much may cause thermal damage to the furnace equipment. It is preferable to set the coke charge amount to 22-25% of the total coke charge amount.

If the charging amount of the central coke is too small, iron ore flows into the central part, and the central air permeability is deteriorated. If the charging amount is charged in the 11th area because excessive central flow may occur and the charging facility of the hearth part may be damaged. Is preferably set to 10 to 13% of the total coke loading.

The furnace heat load is measured by the inlet and outlet temperature of the cooling water, and can be obtained by the following relation (1) using the measurement result.

[Relationship 1]

Furnace heat load = (coolant discharge temperature-coolant inlet temperature) x coolant flow rate

On the other hand, in the present invention, when the furnace heat load is 17,000 Mcal / hr or less, 10 to 18% of the coke content of coke is charged in the second region, and 10 to 13% of the central coke content of the total coke content is in the 11th region. Charged, the remaining coke is charged to area 3-9, and the said intermediate coke mixed iron ore is charged to area 5-9.

When the furnace heat load is 17,000 Mcal / hr or less, coke is charged from the second region, but iron ore is charged from the fifth region, because the activation of the inert portion of the lower portion is promoted by promoting the generation of periphery.

In this case, if the gas is uniform, the amount of coke charged in the second area is set to 10 to 15% of the total coke content, and if the gaseous is non-uniform, the amount of coke charged in the second area is 12 of the total coke content. It is preferable to set to -18%.

Further, in the present invention, when the furnace heat load is 30,000 Mcal / hr or more, 15 to 20% of coke is charged in the 1st and 2nd areas, and 20 to 35% of the central coke is loaded. Charge into the burner zone, charge the remaining coke into zones 3-9, and charge the intermediate coke mixed iron ore into zones 2-7.

If the furnace heat load is more than 30,000 Mcal / hr, coke is charged from area 1 and iron ore is charged into areas 2-7, and the amount of core coke is increased to 20 to 35% of the total coke content. This is to reduce the heat load of the furnace by promoting the flow and suppressing the occurrence of the surrounding flow.

In this case, when the gas is uniform, the amount of coke charged in the first and second areas is set to 15 to 20% of the total coke content, the iron ore is charged in the third area, and the gas is uneven. The amount of coke charged in the first and second areas is set to 20 to 25% of the total coke content, and the iron ore is preferably charged in the second area.                     

In the blast furnace operation method, when the measured furnace heat load is 17,000 Mcal / hr or less, the temperature of the cooling water supplied to the stave is 37 to 44 ° C, and when the measured heat load is 17,000 to 30,000 Mcal / hr. It is preferable to set it as 33-37 degreeC, and to adjust to 27-33 degreeC when the measured heat load is 30,000 Mcal / hr or more.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Conventional example)

In normal operation, as shown in Table 2 and FIG. 2 (a), the coke is charged at positions of 1 notch (4 turns of tilting chute tilt angle) (Table 1) and 2 notches (44.5 degrees of turning chute tilt angle). 30% of the coke charge was charged.

In the case of O / C 5.0, the amount of 120 tons of ore charged per charge and 24 tons of coke is charged, and 18 tons excluding 3 tons of heavy coke mixed with iron ore and 3 tons of core charged to the center of the furnace are 22 turns. 6.5 tons, corresponding to a total of 8 turns, are charged to the 1,2 notches charged to the wall area, so 6.5 tons, or 30% of the coke, of 24 tons of coke is charged into the wall.

When the lower part of the furnace is judged to be inactive during the operation method, the same charging amount as the normal operation is charged over 27 turns using 27 charging modes for inert removal as shown in Table 3 and FIG. 2 (b). Charged 8.7 tons of coke, equivalent to 13 turns, to induce activation.

This accounted for 36% of the total 24 tons of coke, and has been choosing to recover the furnace temperature above 100 ° C by increasing the wall coke.                     

However, in the case of the operating method, when dividing the blast furnace 6 Noguchi As shown in Figure 3 in the radial direction by the wall portion 1m interval area is ^{22.1m 2 = π × 4.8 2 -} π × 3.2 2 to the total area = π × 72.3 Since it corresponds to 31% (13) of 4.8 ^2, the amount of coke charged to the wall area becomes 30 to 39% of the total amount of coke to form excessive ambient flow, and the furnace body temperature is 100 ° C or more over the entire area as shown in FIG. Excessive heat load on the furnace body will be exceeded.

This causes unstable operation such as the occurrence of blown-out due to non-uniform gas flow in the same area.

When this phenomenon occurs, the wall load drop speed is faster than the center portion, so that the inclination angle generated from the wall does not occur, so that the surface of the charge becomes flat. In the case of coke center charging in such a state, as shown in FIG.

When the ore is charged on such a charge distribution, a part of the ore rolls into the center, thereby blocking the central hole of the gas flow in the center, thereby causing adverse effects of worsening breathability and increasing gas flow to the wall.

 In the conventional operation as described above, the charging method for maintaining the wall flow increasing operation direction has a problem in the stable operation due to the non-uniform gas formation caused by the excessive peripheral flow.                     

Notch number One 2 3 4 5 6 7 8 9 10 11 C (suit speed) 4 4 3 3 3 2 2 One OL (suit speed) 2 2 2 One One One Cc (suit speed) 3 Os (suit speed) One One One One Remarks Medium lump coke ratio: 12.5% of total coke content, center coke ratio: 12.5% of total coke content

In Table 2, C represents coke, OL represents allele ore, Os represents small ore, and Cc represents central coke.

Notch number One 2 3 4 5 6 7 8 9 10 11 C (suit speed) 7 6 3 3 3 2 2 One O (suit speed) One 2 3 3 2 One Cc (suit speed) 3 Remarks Medium lump coke ratio: 12.5% of total coke content, center coke ratio: 12.5% of total coke content

In Table 3, C represents coke, O represents ore, and Cc represents central coke.

(Invention example)

As shown in FIG. 5, 15 tons of 120 tons of ore charged per charge and 24 tons of coke charged and 15 tons excluding 3 tons of heavy coke charged with iron ore and 6 tons of core charged to the center are divided into 17 turns. Similarly, the coke induced the ore to be sprayed between the 3 and 7 notches, instead of being scattered in the furnace wall and core.                     

At this time, the turning chute angle was applied to the angles of Table 1 so that the load distribution due to the angle angle variation was not disturbed.

As shown in Table 4 below, a total of six turns of turning chutes were turned to the 1,2 notch areas to be sprayed on the furnace wall during the 17 revolutions, thereby inducing 26% of the total coke to be sprayed on the wall.

This prevented the formation of excessive gas periphery and prevented simultaneous deactivation, leading to stable operation.

In addition, before charging the ore, as shown in FIG. 5, 12.5% of the total coke loading in the coke was charged in the center to form a peak area in the center so that the gas flows well by preventing the inflow into the center during the loading.

If the peak of coke is not formed in the center, it blocks the passage of the gas flow and causes the gas to flow to the weak part of the wall, thereby causing the heat load of the furnace wall.

Ore leads to charging in the middle of the coke charging line and prevents excessive ore from entering the center to prevent gas flow disturbances.

If the charging is continued, the center of the furnace will be the top of the fusion zone, and the area of the chimney-type gas passage will be doubled to the top of the furnace, so that the blowing energy entering through the windhole reaches the core sufficiently to prevent the core from inactivating. In addition, even if the permeability deterioration site in the surrounding, the middle part, the gas can be ejected, so that the stable operation can be performed while preventing the local gas ejection, such as blown out.

In addition, the wall part reduces the strength of the surrounding flow flowing to the furnace wall part by reducing the coke charge amount, and also does not charge the ore into the 1 notch and the 2 notch, thereby decreasing the O / C at the same position, thereby suppressing the inertness and the cap generation under the furnace body. .

Notch number One 2 3 4 5 6 7 8 9 10 11 C (suit speed) 3 3 3 2 2 2 2 O (suit speed) 2 2 3 3 2 Cc (suit speed) 3 X (%) 13 13 13 9 9 9 9 Remarks Medium lump coke ratio: 12.5% of total coke content, central coke ratio: 12.5% of total coke content, X (%): content of total coke content

On the other hand, when the furnace heat load occurs during the normal operation process as described above, the charging load was divided into the case of the furnace heat load of less than 17000 and the case of more than 30000.

When the heat load of the furnace body was 17000 or less, coke and ore were charged by the charging method as shown in Table 5 below, and when the furnace heat load was 30000 or more, the coke and ore was charged by the charging method as shown in Table 6 below.

When the furnace heat load falls below 17000, it is determined that the operation direction is moving toward the lower part inactivation of the furnace, so that coke is removed from the notch 1 notch and charged from 2 notches. The first charge is to guide the light to the wall to be activated.

If it is not activated by this method of operation, it is desirable to activate the coke by making the first entrance to the 3 notch excessively and inducing the coke to be further centered at the same time so that a large amount of gas is supplied to the wall.

When the furnace heat load reaches 30000, it is judged that the furnace heat load is excessively activated, and in the case of gas non-uniformity, the outer wall O / C is increased first to induce excessively developed gass to stabilize. It was.

Next, a charging method was conducted to induce the outermost wall O / C reduction during gas stabilization, and the central charging amount was secured to secure a centrally weakened charging level and a relatively weak center.

Notch number One 2 3 4 5 6 7 8 9 10 11 C (% by weight of total coke content) 16 14 13 8 8 8 8 Cc (% by weight of total coke content) 12.5 O [ore loading (wt%)] 17 17 25 25 16  Medium lump coke ratio: 12.5% of total coke content

Notch number One 2 3 4 5 6 7 8 9 10 11 C (% by weight of total coke content) 10 10 10 8 8 8 8 Cc (% by weight of total coke content) 25.5 O [ore loading (wt%)] 8 17 25 25 25 25  Medium lump coke ratio: 12.5% of total coke content

This operation method is used to switch to the normal operation method when stable, and when the instability of the lower part of the furnace persists, the furnace stave water supply temperature is managed by applying the water supply temperature to the thermal fluctuation width as shown in Table 7 below. As shown in Table 7 below, the number of operating pumps was adjusted to induce activation.

In this way, the furnace temperature could be kept below 100 ° C.

Furnace heat load (Mcal / hr) Water supply temperature (℃) Pump operation number (large) More than 30000 30 3 30000-17000 35 3 Less than 17000 40 2

According to the present invention, not only the stable operation can be maintained through the charging distribution of the most ideal operating state, but also the stable operation is possible by additionally applying the charging and stave water supply temperature controlled operation method according to the fluctuation of the furnace heat load. I could confirm it.

As described above, the present invention induces stabilization of the blowing energy through the charging method when the heat load fluctuates through the inactivation of the furnace in the stave blast furnace to lower the furnace body temperature by reducing the amount of coke coke in the wall to 100 ° C or less, the furnace heat The load can be maintained at 17000 to 30000 Mcal / hr, and the inertness of the lower part is prevented by not charging the ore to the wall. By controlling the temperature, O / C 5.0 or more PCR 170 kg / TP or more, it is possible to maintain the production more than 9500 tons / day, the air flow rate 6000Nm ³ / min or more to prevent the loss of production It is.

Claims (2)

The iron ore in which coke, core coke, and lump coke is mixed by a swing chute installed inside the stave blast furnace is supplied with cooling water to cool the main body by supplying cooling water to the stave provided in the main body. In the blast furnace operation method of charging the molten iron in order, Dividing the interior of the blast furnace into eleven regions (notches) in the radial direction from its inner wall towards the center, and numbering the areas from one to eleven in order from the inner wall to the center; The amount of mixed coke mixed with the iron ore is 10 to 15% of the total amount of coke charged; The furnace heat load is measured using the heat loss of the cooling water supplied to the stave. When the measured furnace heat load is 17,000 to 30,000 Mcal / hr, the coke of 22-25% of the total coke load is 1 and 2 times. Charged in the zone, 10-13% of the central coke of the total coke charge is charged in zone 11, the remaining coke is charged in zones 3-9, and the intermediate coke mixed iron ore is charged in zones 3-9. Become; When the measured heat load of the furnace body is 17,000 Mcal / hr or less, 10 to 18% of the coke content of coke is charged in area 2, and 10 to 13% of the coke content of the coke is charged to area 11, The remaining coke is charged in zones 3-9, and the lumped coke mixed iron ore is charged in zones 5-9; And If the measured furnace heat load is 30,000 Mcal / hr or more, 15 to 20% of the coke content of coke is charged into the 1st and 2nd zones, and 20 to 35% of the central coke of the total coke content is to the 11th zone. Charging, the remaining coke is charged in the area 3-9, and the lump coke mixed iron ore is charged in the area 2-7. The temperature of the cooling water supplied to the stave is 37 to 44 DEG C when the measured furnace heat load is 17,000 Mcal / hr or less, and 33 when the measured heat load is 17,000 to 30,000 Mcal / hr. Blast furnace operation method characterized in that it is adjusted to ~ 37 ℃, and the measured heat load is more than 30,000Mcal / hr 27 ~ 33 ℃

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